Analysis of Pinhol Defects on Alignment Layer Surface for TFT-LCD

The pinholes on the surface of alignment layer was studied, which formed during the TFT-LCD manufacturing process and caused defects of the products. Herein, a vitally typical defect, black spot, was analyzed via FIB, SEM and OMS. The analysis results of statistical software BO (Business Objects) show that the pinhole is the main cause of the blackspot. Based on theoretical analysis and further experimental results, it is found that the hydrodynamic in stability of the solution may lead to the pinholes on the alignment layer surface, and the precure time of the alignment film solution is significantly responsible for hydrodynamic instability. It is noteworthy that the instability needs times to grow full enoughand then to influence the film structure. Therefore, the pinholes on the alignment layer surface will be reduced or eliminated if the precure time is less than or equal to that time.